Universes Collapse
by Nooku
Summary: Frisk had achieved a happy ending; everyone lived in harmony. What could possibly go wrong? The last thing Frisk would have thought would happen was them finding a gemstone that would drastically change their life and their friends'. Faced with a colossal responsibility, they'd travel across a crumbling Multiverse to save all the lives that had been put in danger; and their own.
1. Quite the Unusual Morning

**So sorry for the wait again ^-^" School's got a lot of things on me... this was probably the worst time to start writing again smh. I'm also sorry for not updating CYN first, but this story is my main focus as of now. I'll work on both, but I'll be paying more attention to this. Besides, with all the work I have, working on the two at the same time would be a mess.**

 **Well, this is my first Undertale fic. Hurray(?). Before we start, I must explain a few things about the story to avoid confusion: it takes place not long after the Pacifist ending, with the little alteration of Flowey being taken to the surface as well. Since there are so many stories already, it'll focus on Undertale AUs to bring up something a little original. The ones that will appear are the following: Underfell, Underswap, Swapfell, Outertale, Horrortale, Storyshift, (possibly)Littletale, CORE!Frisk, Ink!Sans, Error!Sans, Dream!Sans, Nightmare!Sans, Fresh!Sans and (possibly)Geno!Sans.**

 **Some other AUs might only be referenced. There are** _ **no**_ **shippings in this, and the story might get a little violent on later chapters. It also includes a few of my headcanons about some AUs - in fact, the whole plot is completely a made-up idea I had once -, but I will still keep their characters as canon as possible.**

 **Before I forget to mention, this story was made up by both me and my sister, so we will both be posting this story to share our work. She will, however, post it to her account on AO3. The only difference between fics will be the author notes, of course. Thank her for any violent or gory chapter you may find later on, she loves that stuff :') Her username on AO3 is "ninecupcakes".**

 **And with this said, you may proceed :)**

* * *

"WAKEY WAKEY, HUMAN!"

Frisk couldn't help but flinch harshly under the white pile of bed sheets heaped on top of them, a short snore replacing what would be a gasp for an awake person at the rude interruption. They didn't even feel like peeking from under the warm sheets that hid them from sight to at least let Papyrus know that he had successfully caught their attention. They were just way too comfy submerged in a sea of warmth, and to be up and about was the last thing written on their mental agenda. Really, it would take more than a harsh, high-pitch voice to get them out of bed. They had already won the battle against their alarm clock, after all. It was always such a nice feeling to keep sleeping after the familiar blaring, especially when they were faced with having to listen to said cue to go to school almost every day.

They were still wondering why it was set to ring at 5 in the morning, though... They never woke up that early, and it was Saturday. Probably a cruel joke set up by a certain punny skeleton.

Speaking of time, it was around 6 in the morning now, wasn't it? Frisk had been awoken about an hour ago by the restless alarm clock, if they remembered correctly, before drifting back into sleep. Since didn't go full-nap again after the loud beeping mere feet away from their ear scared the living daylights out of them, they kind of shifted about, or stared at the ceiling, and vaguely kept track of time out of boredom before sleep caught up to them again. It had to have been around that long ago, though, even if they were too tired to even look at the time. They didn't see the sunlight making its way through the closed blinds yet, and the overall atmosphere just felt like everyone else was fully asleep and dreaming with the little angels.

Everyone but Papyrus, of course. Frisk could feel his eyes staring down at them, cheerfully expecting them to wake up immediately as if they were in some sort of camp. At that thought, Frisk suddenly felt glad that Papyrus was the one to wake them up and not Undyne. Oh boy.

"Pap, go back to bed," the human's weak voice murmured, muffled under the bed sheets, but still loud enough to be heard. "We don't have to be early…" a tired yawn cut off their words. "for anything today…" They shifted under the bundle onto their side, trying to get comfy again – at least until all the bed sheets were pulled away and they were forced to curl up into a ball in discomfort as all the warmth was yanked away from them. Heck, it was a _cold_ morning. Was it winter already...? For a moment, they wondered if opening their sleepy eyes would reveal their room covered in snow. Or an open fridge that had made its way in. Or even an intruding iceberg. All plausible guesses.

"DON'T BE SILLY! WAKING UP EARLY IS GOOD FOR YOUR BONES! NOW, UP WE GO!"

The human sighed in defeat. After all, it was Papyrus we were talking about. There was no way he was going back to bed. And there was no way he was going to let _anyone_ go back to bed for that matter – aside from Toriel and Asgore, out of respect, and Mettaton and Napstablook, who lived somewhere else. Lucky them. But for anyone else, hear the stomping of red boots through the hall or stairs? Take that as a signal for an incoming, skeletal cuckoo bird that won't let you sleep any further. In other words, wake up or he will personally carry you out of bed.

"Okay, I'm up, I'm up."

The defeated human got up to a sitting position, legs crossed, taking a disappointed glance at the now fallen pile of warm bed sheets resting in a mess at the edge of the bed. They missed them already, contemplating them like a lost treasure sinking into a bottomless sea.

As Papyrus noisily opened up the blinds to let whatever little light present outside make its way in, Frisk gave yet another yawn, stretching their arms. A cold sensation ran all the way through their body, causing them to shiver afterwards and hug themselves as they took a peek at the window. There wasn't a single ray of sunshine to be seen, and the sky wasn't entirely dark anymore, but not even the birds had woken up yet. Their eyes drifted toward the alarm clock. It was 6 AM indeed.

Yep, that was Papyrus. Waking up before the world does.

"Are you going to wake up the rest?" the human asked, hopping off the mattress - they quickly tiptoed across the freezing floor with several grimaces as their bare feet touched what felt like ice underneath them, searching for the warmth of their fluffy, purple slippers treacherously placed at the other side of the room. They had been a little gift from Alphys for their birthday a week ago – reason why they had the magenta caps of Mew Mew Kissy Cutie written on them. How she managed to find those, they'll never know; Frisk had literally been dragged to the mall by an ecstatic Undyne yet found no sign of those same slippers. That had been an interesting day.

"INDEED I AM! THERE'S NOTHING BETTER THAN WAKING YOUR FRIENDS UP. IT SHOWS HOW MUCH YOU CARE ABOUT THEM!" Papyrus raised a closed fist to his chest as if he were talking about a heroic act. Frisk giggled silently, rubbing their left eye and tiredly shuffling toward their closet once their feet were safe from the frozen floor tiles. They suddenly regretted sleeping with their short-sleeved pajamas, but all of their warmer clothes were under the excuse of taking the day off at the washing machine. It had probably finished its washing cycle already, but Frisk didn't precisely feel like walking around with damp clothes. Or straight up wet clothes, worst case scenario. "Can Undyne be an exception? Pleeeease?"

Papyrus, having stopped at the doorway, frowned. "WHY? DO YOU WANT TO WAKE HER UP?"

Frisk put several unwanted clothes out of the way as they rummaged through the closet, searching for whatever had long sleeves among the sea of shirts that would belong in a summer wardrobe. "No... It's just for your own good." They turned to face him, a playful smile filling their still tired face.

They still remembered the day when Papyrus got the absurd idea of waking Undyne up at 5 in the morning, on a Saturday too, of all days. Frisk had reluctantly woken up to get a glass of water when they saw him confidently walking towards her room. Before they could even ask, he yelled a not at all careful "MORNING, HUMAN!" before landing three or four powerful knocks on the door to the room Undyne and Alphys shared. He had harshly entered the room, screaming his ill-tempered friend's name as if she were at the other side of the world.

The only reason Undyne hadn't screamed profanity at Papyrus was the fact that Toriel just happened to be walking down the hall for the same reason Frisk was, so the very angered fish lady chose to close the door on his bony face instead. Quite literally, too. Frisk couldn't help but giggle when Papyrus had turned around with a defeated "OKAY, THEN." as he clutched his 'nose' with both hands; Toriel had merely smiled, somewhat perplexed, before asking him if he was okay.

"Remember last time?" The human rapidly put on a blue coat, fluffy as well – they felt adorable with all the artificial fuzz they had on –, as soon as they saw it through the corner of their eyes. They hugged themselves again after closing the wardrobe and turning to face Papyrus, looking at them with a confused and pensive frown.

"YES I DO! AND MY NOSE DOES AS WELL. SHE WAS PROBABLY HAVING A BAD DAY. TODAY SHE WILL BE HAPPY TO BE UP EARLY, SHE APPRECIATES MY HELP!"

"So, you're _going_ to wake her up?"

"YES."

"Are you sure?"

"NEVER BEEN SURER!"

"…then that's my cue to go."

Frisk shuffled out of the bedroom, Papyrus' eyes following them without catching the fair warning. Frisk smiled the whole way out. A part of them kind of wanted to stay just to have front seats to watch Undyne's reaction, but that was probably a bad idea. The only things that could happen were either becoming deaf due to furious screams, having to dodge out-of-control spears, be part of a chase, all of them together, and so on. The list was long, and Frisk didn't precisely want to be a part of it. They would've tried to talk Papyrus out of it if it was possible. It wasn't, so better they'd move on. Hey, at least everyone would be awake after the earthquake that was about to take place. And that could only mean one thing: early breakfast.

With their mind gleaming at the thought, they quietly stepped down the stairs, making their best attempt not to wake up whoever was still sleeping, unlike Papyrus who could already be heard strolling towards Undyne's room. Frisk couldn't stop the unstoppable, but they wouldn't make it any worse. Whatever was about to happen, they had to stand aside. Neither Toriel nor Asgore would really appreciate screams and whatever Undyne was capable of doing when mad at such hours, and the human would try their best not to be blamed as well.

As they came down the somewhat creaky stairs – they had to tiptoe their way down to avoid drifting any survivor against the skeleton's morning call out of their sleep –, they figured out Papyrus had already tried (in vain) to wake Sans up, as they found him slumped on the couch and sleeping like a log. If Frisk had Papyrus' place, they would have stopped trying to get Sans up and about long ago, because that was even more unlikely and impossible than Undyne not being even slightly mad at being yelled at at 6 in the morning. One could scream at him, play the loudest song ever created, heck they could explode the entire house and he would continue to be Sans. Well, maybe not, but examples, examples.

Frisk had to give a glance at the kitchen. They felt driven towards it, but decided not to eat anything yet; they preferred to wait until Toriel's morning pie got everyone's attention. Sure, the chocolate bars and cookies hidden away in the fridge and pantry were really tempting, but Frisk would rather have their favorite pie as first thing to eat. They could still persuade Asgore to let them have at least a single cookie as well. All in all, they'd find their way to get both delicious snacks without Toriel telling them not to eat such amount of sugar.

They flinched slightly when they heard the powerful knocking on the room upstairs, soon to be followed by whoever of the two started screaming their lungs out first. No wonder Frisk wanted to take the risk of going outside until everything settled down, despite the could that would probably be lurking beyond that door.

"UNDYNE!" they heard Papyrus sing-song. Yep, right about time to go.

Frisk quickly opened the door before the explosion of tired, early-in-the-morning anger came up and caused an earthquake inside the house, and casually shuffled outside with a fast gait as they further heard Papyrus screaming for Undyne to wake up.

However.

They couldn't help but stop midway before fully closing the door. Frisk stayed put for a couple of seconds, hand holding the golden doorknob, and peeked back inside as the thought of missing such scene suddenly felt like a crime. What was about to take place seemed more tempting than some treats or a cinnamon-butterscotch pie were at the moment. And coming from Frisk, that meant it was really, _really_ tempting.

Soon enough, Undyne's voice roared the early skeleton's name like a lion would angrily roar at an intruder before chasing it off. She bellowed something along the lines between "not again", "come on" and "get outta here", and not ten seconds after Papyrus disturbed her sleep, they were both running with a giant's steps down the stairs - one running away in panic with the other hot on his heels and a glowing spear in hand, remaining pupil shaped in a menacing slit.

Alphys had gotten out of the room in alarm, but decided not to join the absurdly senseless 'chase' and stare from the banister. Good thing she was awake with her face glued to her laptop screen and not asleep; the scare she would have been given would've been one to remember.

Sans was awaken by the booming quartet of feet making the wooden staircase tremble, but only took a mere, tired glance at the stairs as his brother continuously screamed "SORRYSORRYSORRY" all the way down in a tangle of words, quickly turning left, lunging into his bedroom and closing the door with a slam that made the entire house jump from the impact. Undyne, looking like an out-of-control train sliding through its railings, practically leaped off the last three stairs, but stopped right in front of the door before slamming it down - she would have probably crashed had she not jumped off and been forced to crouch as to not lose her balance. Wouldn't have been something too savage to find its place inside her mind…

Spear still on her hand, she thought for a moment to stab it through the door as her way of leaving it clear to leave her alone, thing that wouldn't have surprised anyone, but she didn't want to risk downgrading her friend to a bony head-kebab, and set the glowing weapon down with a sigh. A toothy grin replaced a scowl that could have scared a vicious dinosaur off, and Frisk almost frowned at the lack of bellowing and smashing that they were expecting from the very beginning.

Once she seemed to calm down, or at least calm down the Undyne way, Sans slumped on the couch again, merely deadpanning a tired, "morning." Undyne only gave him a sideways, frowning glance. She seemed to be in a good mood despite everything. Papyrus was lucky. And Sans too. And everyone in the room. Frisk giggled, only their head peeking through the door. It hadn't been a wreck, but it had managed to cheer them up and get those little specks of sleep floating around them to go away. They were ready to start the day.

Undyne's fin twitched slightly at the sound of childish laughter, only then noticing the human. Her expression still seemed unimpressed as she stared at Frisk, not even wondering what they could possibly be doing outside with their pajamas at 6 in the morning. "Oh yeah, real funny, punk." was all Undyne said before storming back upstairs, spear vanishing into nothing. Well, maybe she wasn't in _that_ much of a good mood, and probably the only reason she hadn't screamed at everyone she could find or threatened them with a spear was because she just didn't feel like it, but she took it a hundred times better than she would have usually had. Perhaps a thousand.

The door to the skeletons' room slowly creaked open, a black-eyed, shaken frown showing up and scanning the living room. Seeing that there was no ocean warrior waiting outside to lock him on a noogie spree as punishment, Papyrus opened up fully and stepped out. He still managed to catch glimpse of Undyne slamming the door to her room shut behind her; Alphys found herself flinching and taking a couple of tiny steps forward as the door closed down right behind her tail. Her expression was one of confusion as she stared down at Papyrus, who stared up, not at her, but at where Undyne had been a second ago.

"Told you," came Frisk's mocking voice like a little child would mock someone when proudly proving a point.

"WELL. AT LEAST MY NOSE IS OKAY! I THINK SHE WAS HAVING A BAD DAY AGAIN. . ."

"nah. i think her reaction was pretty a- _door_ -able."

Of course. There wasn't a morning without Sans' puns to brighten up the day for anyone bored enough to crack a chuckle - Frisk did though, and Alphys smiled almost nervously as she stepped down the stairs.

It only took Papyrus half a moment to catch the joke. "SSSSSAAAAANS!"

Ironically, Papyrus started out being the most cheerful monster awake, ready to make his day, and everyone else's, as great as it could possibly be, and ended up being the most annoyed one. Well, both he and Undyne, but the not-so-eager skeleton seemed a little more irritated than she was just by that one pun alone. And for the fact that his brother was still slacking off despite the fact that he had gotten him out of bed a few minutes ago.

"IT'S TOO EARLY FOR YOUR PUNS! AND WHY ARE YOU STILL SLEEPING? I TOLD YOU TO WAKE UP AND GET OUT OF YOUR ROOM!"

"i did. this is the living room, not my room."

"THEN DON'T SLEEP ON THE COUCH!"

"'kay."

Sans tiredly got up from the couch, and shuffled past his little brother. "WHERE ARE YOU GOING?"

"you told me not to sleep on the couch, so i'm going to my bed."

"THAT'S NOT WHAT I MEANT!"

And so, their usual day starts.

As the skelebros started their often endless 'argument' and Alphys went to take a can of soda, Frisk calmly walked towards the backyard. Normally, they'd feel weird walking outside with their pajamas, but the few people and scarce monster that would be roaming through the streets so early on a Saturday wouldn't mind a fluffy child going to the garden behind their house.

It turned out that the air was nowhere near as cold as their room was. In fact, the atmosphere was pretty nice, right there between not too hot and not too cold. They yawned once more as they got to their final destination, taking a look at the bushes as always. They developed a liking for gardening, taking every chance they could get to work on the yard with their foster parents. Asgore had recently started trimming a hedge in the shape of Papyrus' body instead of his head only, and looked great despite being a work in progress. Frisk had helped on it just yesterday. The air was pure, and flowers all around were so well cared for that Frisk felt like they were smiling at them.

"You look stupid."

Speaking of flowers with feelings.

"Gee, thanks Flowey. I try hard." His stem bent downwards with an irritated grimace at Frisk's lack of interest towards his usual morning hostility as they laughed it off with their typical mischievous grin.

Flowey looked tired as Frisk dragged a chair and sat down on the wooden table he was on. He had been awake the whole night, after all. It wasn't like being stuck in a ridiculous flowerpot left him enough freedom to do much else, but he wasn't about to complain about that. A couple of days after being brought back with them, it became a usual thing for him to just contemplate the sky. He had never seen the surface in his many years of existence, and even despite his lack of emotions, he couldn't help but be impressed by it.

Frisk recently found out that he liked the clouds. He found their shapes interesting, and was always looking up at the sky when he was left outside or near a window. The sunsets were mesmerizing to him, his eyes being drifted away by the beautiful yellows, reds and oranges that painted the horizon. The stars glowing at night soothed him, and he almost always found himself staring into the moon.

It was only at night when he didn't mind company.

Really, that was just about the only thing he had openly liked about the surface, and probably the only thing he would honestly like. And yet, Frisk was happy for him. And so were those who cared about helping him out. At least, he had _something_. They knew Flowey would never admit it in front of someone, but being out there was entirely better than staying in the Underground with nothing and no one. Even if he had almost fought Frisk in an attempt to stay trapped in that prison as opposed to living a life with beings that had his wellbeing in mind. He deserved to be happy, but Frisk was the only one to truly know why.

He wasn't just a lonely creature that needed help, as Toriel and the rest thought. But he and the human had made a deal. Never reveal his identity, and he would never hurt anyone. Unless provoked.

"So? How's your day going?"

Flowey glowered at Frisk, their elbows against the table and hands holding their cheeks. They were a little too close for comfort. Not that he cared all that much, though. Flowey already knew Frisk well enough to not even bother trying to get them away.

"Better than yours I guess." The flower's voice was neglectful. "I heard Papyrus and his fish friend screaming. What was even happening?"

Good. A conversation topic. Frisk was progressing. Usually, Flowey would entirely avoid starting a conversation himself. That was one of the main reasons they kept pushing him. They had to give him something to do that didn't include blood, dust or overall death. Unlike him, Frisk had hope. Flowey knew - or, _thought_ he knew that he was a lost case, but the child never gave up on him. They didn't know if he appreciated it or not, but it was fine if the answer was no. They were doing a thankless job at will, that was what mattered to them.

Everyone could find that little sparkle of kindness deep down.

"Well, Pap got this idea of waking people up early, and let's just say _Undyne_ ," they put emphasis on her name in an attempt to get Flowey to at least have it sound familiar - that's how much he cared about the rest, they were just 'the nerdy one', or 'the angry piece of sushi', or 'the annoying robot', etc. for him. "didn't take it all that well. She didn't break something, or someone, though, so it's all good."

Flowey's stem bent downwards in boredom as he looked away and murmured a quiet "Fantastic," that the human wouldn't have caught if there was any more noise than the morning breeze waving the bushes' leaves. Frisk would have probably gotten more of Flowey's attention if they had told him that Undyne burned the house down or something. Well, there was an 80% chance of it happening someday. At least they'd give Flowey a topic he'd genuinely like to discuss.

"So, Frisk," said human looked at the flower. He was talkative that day, even for a bit. That was nice. Most other times they'd have to force him into a conversation... and that often ended up with 'friendliness pellets' flying all over the garden if he so happened to be in a bad mood. "What do you make of that?"

Using a small root as an arm, he carelessly pointed somewhere to their left. Being in a backyard with nothing but flowers and bushes, there wasn't much to catch someone like Flowey's attention, so his interest had gotten hold of the human's curiosity. When Frisk looked over, they expected to see anything but what they actually saw.

Right there, between a couple of shrubs, a purple glow painted their leaves. It seemed to be inside one of them.

Frisk couldn't quite manage to understand how they missed a glow that could have very well belonged to a flare, but they still missed it, and there it was. Even someone drunk not paying attention to their surroundings would have seen it. "It's been there all night. Took a little nap and next thing I know the bushes are glowing." Even though Flowey sounded unimpressed, Frisk also knew him well enough to tell that such strange occurrence had caught his interest, and it was his main focus to figure out just what on Earth was it that the glow belonged to.

Curiosity taking over every inch of their body, Frisk approached the eerie shine, ideas racing through their mind. Perhaps it was some sort of toy that a kid hurled over the fence, or... Or. Actually, there weren't many choices to choose from, fact that made Frisk stop for a moment. It looked otherworldly. It could be dangerous for all they knew. What are the odds of finding something glowing in a strange purple on your completely normal backyard?

But, Frisk was a curious child. And determined. Curiously determined.

Frisk crouched in front of the bushes, and rummaged through the leaves; whatever it was ended up being small, because they couldn't make eye contact with it yet. They immediately knew it wasn't some bioluminescent monster, or just a monster using magic. Choices started to grow thinner.

It was then when Frisk's fingertips came across something that wasn't a sharp branch, something small and smooth, seemingly buried in the soil. They couldn't see it, as it was hidden right between the tangle of branches in the middle of the two bushes, so they'd have to rely on luck to pull whatever it was out.

"Did you find something or what?" Flowey yelled rather impatiently. He really seemed to be curious about whatever that thing was, but really, who wouldn't be?

"Almost," Frisk had to stretch their arm to get a sure hold of the object. They were so concentrated in preventing it to slip from their precarious grasp that they hadn't realized it stopped glowing, as if it had been trying to lure a curious one. Flowey did, though. He didn't like it one bit.

The human stood up slowly, eyes fixed onto the strange object they had found.

It was some sort of carved stone; a purple spiral with sharp edges, about the size of a ping-pong ball and really thin. It was pleasingly smooth. Lighter purples decorated the center and the sharp end, and a blurred tonality of black gave it an otherworldly feel. It was beautiful, yet eerie. They had never seen anything like it, it was almost as if it had come from another world.

"So? What is it?"

Flowey's voice took Frisk out of their trance. The spiral was still glowing, albeit very slightly. They found it difficult to take their eyes up off it. "I don't know," they replied blankly, walking towards the flower as they further inspected the gem. "A carved stone or something. It's pretty interesting."

Flowey extended a root, giving Frisk the cue to hand it over. For just one second, they doubted. They didn't want him to break it if he didn't like it. It was something Flowey enjoyed doing: he finds it useless? In pieces it'll end. It was a huge relief for the kid to see that he took it carefully and eyed it the same way a baby would contemplate a toy for the first time. Awe and curiosity could be read on his face.

"I didn't know stones could be this smooth," he commented, Frisk resting their torso on the table to get a closer look at the spiral.

"Yeah. It could be from a collar... but why would it glow like that then?"

Flowey slightly moved the root down and stared off into nothing - realization. They could be called crazy, but they both knew that it was no ordinary object. It had been glowing like the light on a beacon, and stopped once it had been picked up. It was definitely not a toy.

So, _what_ were they staring at...?

"Maybe... It's a crystal from the Underground?"

Frisk's idea wasn't that farfetched. Monsters did primarily use crystals to guide themselves, and Waterfall had more than a few examples of them. No, they didn't glow that way neither were they smooth, and Frisk hadn't met anyone who carved crystals down there, but it was the most possible option they had.

Flowey handed (rooted?) it back to Frisk. They let it rest on their extender palm, expression heavily pensive. "We should take it to Alphys. She's a scientist, she'll know something about it, right?"

The flower did his best attempt at a shrug. He cared, but not that much.

"I doubt your Alphys would be able to tell what that is, Frisk."

Both human and flower jumped, and next thing they knew their eyes were frantically looking all around them. That childish, monotone and echoing voice could have very well belonged to a ghost. It sounded so close, yet so far. There was nobody in the backyard but Frisk and Flowey, despite the fact that four eyes had every single inch controlled.

"Who's there?!" Flowey menacingly screamed, forcing Frisk to back away as several bullets summoned behind him; the human clenched the hand holding the gem as if they were protecting the most valuable object in the world.

"Don't worry, I'm not a threat. Don't bother, Flowey, you cannot hurt me."

"W-who are you?" Frisk would have grimaced at how weak their voice sounded had they not been as scared as they were. _What was happening._ "H- how do you know our names?"

"Come on, show yourself!"

"I am here. Turn around."

They both did as told with a moment of hesitation, looking behind them equally as slowly - complete unison. Frisk's heart dropped in shock as they felt like they were looking at themselves in a mirror which took all color away, because they saw _themselves_ in a greyscale.

They had to gasp and take a step back. They couldn't hold it, it was purely a reflex.

Yes, they were staring at themselves. A monochromatic Frisk, with a warm smile on their face that still seemed sweet despite the two black holes that were their expressionless eyes.

"Hello. I'm Core Frisk, and what you've found is the Nucleus of the Multiverse."


	2. A Door to a New World

Papyrus and Undyne screaming? Logical.

Sans being Sans? Of course.

Alphys awake? Not so usual, but still passable.

Flowey feeling grouchy? Indeed.

A ghost-like Frisk appearing out of nowhere? Nuh-uh.

Frisk didn't know if it was due to their inner fear and general disbelief over the situation, or if it was actually happening, but the air that had been so comfortable and peaceful just seconds ago suddenly felt cold and treacherous, raising goosebumps on their skin that extended all over their body like a shockwave. For just a moment, the atmosphere was so sinister and eerie that they couldn't help but think that standing in the middle of a lightless graveyard as portrayed in a horror story would make them feel just as shaken as they were there.

During that one surreal moment, the human that was always gladly willing to help anyone in need, monster or not, didn't know what else to do but stare at their colorless self who spoke with a distressed speech, an almost teary voice that sounded like two childish ones, whispery, attempting to overlap one another. It gave off a phantasmagoric feel that didn't help in getting Frisk's goosebumps away.

Unbelievable or not, Frisk was staring at themselves, and yet the monochromatic human felt like a completely foreign and otherworldly creature that couldn't compare to the real one. They found themselves staring into the two black holes that were Core's eyes, and were almost hypnotized by them. Those eyesockets were expressionless, wide, and that combined with their lack of color made Core as a whole nearly disturbing to look at – and yet, Frisk couldn't stop doing so, as if the blackness belonging to their empty eyes had caught them with a rope of curiosity and awe that wasn't willing to let go.

It only projected their fear further, though, but they couldn't help it even if they wanted to. They didn't know or care if they were dreaming, going crazy, or actually seeing what their distraught eyes showed them; all they knew was that they were face to face with another Frisk, and it felt as wrong and eerie as an upside-down world. In fact, seeing the sky and clouds below them, with the grassy earth as a green and brown ceiling, would be considered an everyday sight compared to pretty much everything else that was going on at that backyard.

A glowing gemstone appearing overnight, followed by the unexplainable appearance of a greyscale Frisk? Even an unforeseen apocalypse was more believable.

Flowey exchanged lost glances between children, the pellets that endlessly twirled above him seeming forgotten. He didn't know what he was waiting for, if anything at all. He just knew that his little discovery was causing a chain of paranormal events, and he wasn't comfortable with that. He didn't know if to ask something, or attack, or tell Frisk to do the first thing that landed on their mental bag of ideas that seemed to be bottomless. The barrage of mixed thoughts messing with his mind was confusing him to an unbearable point.

Flowey hated confusion. He didn't like to doubt, especially not when around someone whom he could easily kill such as a human youth. Or, a human youth _and_ a human ghost, if we're being specific. He wanted to know what he was doing and why he was doing so. He wanted to know why others did what they did. He wanted to understand the situations he found himself in, albeit through his viewpoint only. The second everything started going off-track from his mindset, he felt like he was in the wrong; in other words – or rather, _his_ words –, useless. He felt like an idiot who was lost in a sea of mocking choices without hands to reach out for one.

It made him irritable. _Mad._ It made him want to start flinging bullets all over the place, all in an attempt to make himself look like the only one who knew what was happening, the one holding the power.

But, he chose to cope with having no other option but to wait and see, as he found himself having more trouble trying to understand the whole situation than someone attempting to find a grain of salt hidden within a pile of sand. It was a half-impossible puzzle, with its million pieces scattered all over the place, one that even Papyrus would give up on; Flowey couldn't picture himself searching for the lost pieces and solving it, despite his inner curiosity keeping him aware of any hint that could be given to him. It was his curiosity that kept him hooked onto the situation, too, and stopped him from making everything go to waste.

For once, he was part of something interesting that he could interact with. Something _new_. He wanted to enjoy that moment while it lasted, no matter how freaky it was.

"I know this is too much for you now," Core spoke softly; their eyeless gaze seemed fixed on the glowing stone on Frisk's slightly trembling palm. "but we don't have much time. I need you two to listen to me, _please._ "

Their honest beg was enough to snap Frisk out of their trance, to get the swarm of thoughts away in order to clear their mind for brighter ideas to make themselves at home. Perhaps Core was something that their active imagination was projecting, or perhaps Frisk was actually seeing someone such as their gloomy double. All in all, they were indeed an almost dark imitation of themselves, but the ghost-like human needed help and they were going to give it to them, no matter what. However Frisk, still rather insecure after failing to fully shake their nervousness away, nodded once, slowly and silently, but with confidence lightly written on the small movement.

Flowey, by the other hand, only directed Core a characteristic, apathetic frown that the monochromatic child didn't seem faced by. He was staying to figure out just what on Earth was happening, not to help a colorless reflection of a human he still hated.

Frisk felt an army of questions gain force on the back of their mind, fighting to get out and see the light of an answer, but they held them off. As exciting yet disturbing it was to be faced by yourself, they had to listen to whatever they had to say first. They were troubled – _heavily_ troubled judging by their voice, and Frisk wouldn't waste a single, minuscule second of their time with awed questions; those could wait.

"Frisk, what you're holding now is the most important thing you'll ever hold in your life." Encouraging. The human flinched as the words were spoken, glancing down at their palm and not even stopping to wonder how their greyscale double knew their name – then again, they were Frisk too. The so-called 'Nucleus of the Multiverse' kept emitting its faint glow, tinting their hand purple, and suddenly, something so small and light felt enormous, heavy with importance. As to which type of importance, Frisk wasn't sure, but it had to be something really important to catch someone's attention like that. Core really was bent in protecting it, making the spiral seem like a fragile piece of porcelain at the edge of falling from high up.

Frisk had a vague idea of its value, though. Core had mentioned the Multiverse... but _what_ was the Multiverse, anyways? It sounded like something that came right out of one of Alphys' comics; in fact, the whole situation could belong in an anime episode, but that was just Frisk's mindset after watching an all-too-long anime marathon with a nerdy lizard and an ecstatic fish lady yesterday.

It was intriguing either way. When hearing a word such as 'Multiverse', their mind immediately showed them a bunch of galaxies in the middle of the open, starry space, all close to each other as if it were a spatial meeting with the many different worlds sharing their own stories. They didn't know what else to think of; they hadn't heard anybody use that term, not even Alphys. Was it even a legit word? Was it what they thought it was? It was a possibility, too, that 'Multiverse' was Core's way of referring to the universe as people knew it, for reasons unknown to human and flower.

Frisk didn't want said Multiverse to be their world as a whole. That would mean that they all were in danger, that their world could be at the edge of a disaster. Their expression shifted to one of worry almost involuntarily.

"Now, don't worry, it's not as fragile as you think it is." Core reassured, taking a couple of small steps forward with legs thinner than sticks as they misread Frisk's emotion as one of preoccupation toward the glowing stone. They didn't approach too much, or too fast. It wasn't their intent to cause Frisk any more discomfort. They were mindful of how odd their presence was for them, and they wouldn't blame them for it. "But you're still holding the life of many people. I just want you to be careful." A light smile shaped their gray face into a honest, kind expression, with only small specks of concern adorning it.

A very confused and troubled human glanced down at the spiral again, only then catching glimpse of Flowey eyeing it with bewilderment. Frisk just hoped the whole 'holding the life of many people' statement hadn't given him any funny ideas; the child had pulled the Nucleus slightly closer to their chest with preoccupation, but the flower didn't seem to catch the noticeable distrust. As much as they regretted it, they couldn't fully trust Flowey yet, despite their tireless tries.

The army of questions was becoming greater, not with questions for and about Core but with questions and wonders about the Nucleus too. It almost felt like a headache, and they had to get at least one of them out of their mind before it burst.

"... what do you mean by holding the life of many people?" their voice, surprisingly for them, was small, almost fearful.

It would have been impossible to stop and think about the first question to release. Their subconscious would make them either ask everything ahead, or leave them locked trying to figure out which question to use, so they put their curiosity aside and let out the most recent bit of information they had received. That one statement had worried them too much. Frisk was helpful, yes. They cared for the world around them, yes. But the future of monsters was already at their hands and everyone but themselves considered it to be too much of a responsibility for a child. Frisk was fully willing to do it; however, the fate of an entire world...? That had disproportionate measures.

 _If_ the fate of an entire world was indeed at their hands, of course.

Core gave their own, small nod, and they looked thoughtful. Their smile remained. "I had a feeling you'd ask that. I know you have many questions, and I will answer all of them, but not now. You need to bring everyone with you first."

"This situation concerns you the most, Frisk." The more colorful human gulped a sudden burst of nervousness down. "But the others must know too. So, I need you to make me a favor. I'll be able to clear this up for all of you afterwards." Their face shifted, slowly, to show a hopeless expression on their empty eyes; it nearly took away all of Frisk's pity, but Flowey, whose attention was back to them, remained indifferent. "Will you...?"

The chilly air, the strange atmosphere, the army of thoughts, all of it was immediately erased from Frisk's mind as they adopted a confident posture. They still didn't know what was happening, and probably would never fully understand it despite the upcoming answers, but they would help either way.

They didn't understand the Underground back then, either. It all was otherworldly, strange, scary... A whole new world for them. They didn't fully trust anyone at first, the monsters' intentions unknown to them. All it took was some courage, kindness and determination to come back home with true friends that would never leave them behind.

There was no difference there.

A warm smile adorned Frisk's face, one as kind as Core's was as they innocently asked for help. "I'll do it," they proudly stated, earning a grateful smile from the monochromatic child but an 'are-you-serious?' type of frown from the sentient flower. "But... can I at least know for what?"

Core gave a small, almost inaudible sigh as they looked up at the sky – Frisk and Flowey followed. It was painted a beautiful purple, with hints of becoming a dim pink soon as the sun slowly made its way out; thin, grey clouds decorated it like ribbons on a Christmas tree. The moon could still be seen on its way towards the horizon, soon to be out of sight. It was a soothing view, and Frisk could once again feel the air as relaxing as it was supposed to be, and not cold out of subconscious fear. "You will know... but not here." Core said calmly, earning the other human's attention.

"W-why not?"

"We don't have much time, and we may not be safe here. Not as long as you're holding the Nucleus."

Frisk had to give a hitched breath, almost, just almost making the motion of throwing the gemstone away from their grasp as if it had caught on fire and started to burn through their skin. They would have never dared to, though. Unless it had truly caught on fire. "There is only one place in which you'll be surely safe, but you'll have to get there for yourself." Before Frisk could ask about Core's words, sounding like a riddle on their confused mind, they continued, "Tell your friends about this, then come find me. All you'll have to do is think of a blank space, and open any door you want. I will be waiting on the other side."

Frisk remained silent for a few seconds; it didn't make any sense. Why- _how_ would that be possible? Why would thinking of a blank space as they opened a door be any different than opening one thinking about anything else that could roam their mind? And why couldn't Core just lead them to wherever they had to go to 'be safe'? – and safe from what? The questions were starting to get unbearable, rendering the human unable to think properly. It was too much. Way too much. And thanks to the utterly puzzled expression they hadn't realized they were making, Core caught up to their troubled mind.

"Frisk, you're thriving with questions, I know." they said softly, an understanding tone caressing their doubled voice. "Don't question it, just do what I've told you. You will understand, I promise."

Frisk, not knowing what else to do, nodded again. It was more of a rushed nod than an honest one that time, but the monochromatic human accepted it. Flowey wasn't all that willing to play along, though, as noted by a scowl dull enough to wilt common flowers.

"And why the heck should we believe you?" he rasped, pellets twirling faster as a clear threat, but Core didn't even flinch or step back, unlike Frisk who had an anxious glare right on top of the flower. "You just come out of nowhere, and think we're gonna help you? Why would we?! We don't even know you, freak!"

And much to the two's surprise, the colorless ghost of a human only gave out a little, childish laugh. "Oh, you Floweys, always so sympathetic."

The flower's left eye twitched, teeth gritted in a clear show of anger that Frisk didn't like one bit. "Why you little-!" The human stepped aside in fear of a bullet storm suddenly raging around them, Nucleus shielded by both of their hands, but Flowey stopped his incoming attack, beaming with indignation, to show a frown that replaced every single bit of enragement he had shown before. All the bullets disintegrated in mid-air. "Wait, did you just say Flowey _s_? As in plural?"

Core only giggled again. "You'll both understand."

Human and flower were taken aback as a piercing white glow suddenly engulfed Core, making their body waver and start to vanish like a specter in fiction. Flowey's stem bent downwards as he attempted to shield himself from the blinding light, as so did Frisk with the one hand that wasn't holding the purple stone.

And just like that, it was over.

The blinding light disappeared, and Core was no longer there.

Releasing a small gasp, Frisk looked all around them. To their sides, upwards, downwards, in front of them, behind them; their head and eyes inspected every area, moved in every direction known to humankind. Their colorless self had completely vanished out of thin-air, and the only thing that reminded Frisk that such thing had actually happened was the Nucleus. And as they frantically searched for the gone ghost, they kept directing _whats_ and _hows_ and _whens_ to nobody in particular, almost expecting a small breeze to answer their useless questions.

Flowey kept his astonished gaze fixed on the spot where Core had been standing on seconds ago, looking at the grass as if it were an alien presence. He had no idea of what just happened. He didn't know if that actually happened. He only knew that he had been laughed at by a ghost, and said nothing else as Frisk exchanged perplexed glances that went from the stone to where Core had been, up and down and down and up – they did that about five times in a row, each of them expecting to look up and either see Core there again or lose sight of the Nucleus, then knowing it had all been a freaky hallucination or dream of theirs.

What they saw never changed, opening their mind to reality.

"Did- did you- what- _did you see that?_ " Frisk, between crisscrossed and broken words, nearly breathlessly screamed at the flower like an impressionable youth having found something new. Flowey slowly turned to face them, his face being the pure representation of a _meh_. He blinked once before deadpanning an almost lifeless, "Duh.", all the while glaring at Frisk with an expression that could wilt flowers _and_ humans.

However, Frisk, ecstatic after the utterly paranormal event, part of which was still being held by their hand, didn't even give a grimace in response to Flowey's dull answer and walked around in circles or straight lines as they attempted to clear all the blur that clouded their mind, fallen leaves and sticks crunching here and there beneath their feet.

"That... That was... Did that actually happen...?"

Flowey paid no heed to their rambles, knowing they were asking nobody, as he submerged into his own mind. He had lived for a long time in a world crowded by monsters of all shapes and sizes, with all sorts of magic at their disposal. He had seen so many crazy and unthinkable things, strange events and creatures with insane powers and abilities. And even knowing such beings existed, Core was still the icing on the cake, a senseless enigma misplaced in a sophisticated document. A ghostly human, able to seemingly teleport. Intriguing beyond words.

Especially having in mind that humans couldn't take on the form of ghosts like monsters could, and lacked the magic resources needed to teleport like that. So... what was that all about?

He was drawn out of his thoughts as he caught glimpse of Frisk walking back home, head down in thought. Wanting to give the situation his own ideas, he couldn't care less about whatever they wanted to do, but he still interrupted himself to look up at them. "Where are you going?" he asked, curiosity nonexistent on the question.

The human stopped their fast gait, turning to look at the flower. "I said I would help. And... I don't really know what just happened, but I'm not going to ignore someone who needs me."

Flowey only sighed, almost with irritation, as Frisk kept marching their way. He still despised their attitude. Help or be helped, laughable.

Soon, the sound of the door closing gave room for peace to take over the backyard. Finally, loneliness, even though Flowey wished he hadn't needed to go through so much just to be alone.

In reality, Flowey really didn't care about that ghost of a human, or about the glowing stone that Frisk was definitely going to keep like a treasure. He just found it all intriguing, nothing else. Besides, there wasn't much to do up there. He knew he'd be better off tricking his mind with questions and made-up answers for his little, freakish encounter.

* * *

Frisk winced as soon as they opened the entrance door, action that revealed them the living room redecorated with a glowing spear lodged right next to the door to the skelebros' room. Papyrus had probably encouraged himself into waking Undyne up a second time, or the aforementioned warrior decided she hadn't reacted properly according to her standards and got the idea of adding a hole in the wall. All in all, a lethal weapon was still dangerously close to a door. Did they care?

Not really, seen such thing too often. And worse, too. It was nothing compared to their backyard story, anyways.

As they quietly made their way in, slowly closing the door behind them with their one free hand while the other, clenched, shielded the purple stone, they hoped certain loud skeleton had managed to wake everyone up. Despite the importance of the situation, Frisk thought it was rude to wake people up just to tell them an unbelievable tale that would probably sound like a lie through some ears - or skulls, if either of the two skeletons happened to not believe it. Their bet was on Sans in case their anecdote did sound like a crazy lie.

Oh, wait, it did.

Frisk rhythmically knocked on the door nearly decorated with a spear to a short and nonexistent beat, soon being forced to step back as it was immediately flung open by a red-gloved hand. "OH, HI HUMAN! GOOD TO KNOW YOU'RE NOT SLEEPING AGAIN! THAT MEANS MY DEDICATION WORKED! . . .FOR SOMEONE."

Papyrus was in one piece and as cheerful as always. Good, that meant Undyne had decided to direct her anger toward the wall only... they couldn't help but think about how mad Toriel and Asgore would be about it.

"Heh, yeah..." only then it came to their mind that the sole reason their entire backyard tale had even happened was thanks to Papyrus. Who'd knew?

The child used a finger to point at the spear, though, before getting into the actual subject. Frisk was curious, that was all there was to it. The skeleton took a step out and looked at it intently, for three our four seconds before realization illuminated his bony face. "OH, THAT! AFTER UNDYNE GOT MAD, I WENT BACK TO SAY SORRY. AND TO TELL HER THAT SHE GOT TOO ANGRY AND SHOULD RELAX! AND THEN SHE CHASED ME AGAIN AND FORGOT HER SPEAR THERE."

It was an interesting morning, that was a fact.

"Huh," was Frisk's response, with half a smile. "So, Pap, is everyone awake?" they asked, their low voice highly contrasted against the skeleton's powerful one. They doubted a negative answer. After all, Undyne got mad two times in a row - that was more noisy than Papyrus personally telling you to wake up.

"YES, ACTUALLY! ASGORE AND HIS CLONE- I MEAN, TORIEL WOKE UP RIGHT NOW!"

Internal sigh of relief.

"Good... I need you all in the living room," they began, waiting to reveal the gem later on where their oddball family could give their honest opinions together. Frisk slightly leaned to the right to peek into the room and, with a louder voice, said in a mocking sing-song way, "Okay, Sans?"

Said skeleton, stepping into sight as he stretched his arms, gave them an equally mocking thumbs-up along with a grin that never faltered.

"WHAT DO YOU NEED US FOR?" Papyrus excitedly chimed in. "I WILL GLADLY TELL EVERYONE ABOUT IT!" He made to confidently step out, but the human reflexively waved their hands frantically in a negative motion.

"No, no, it's okay, I've got this. I just need you for... a little story." They smiled innocently.

"WOWIE! STORYTIME IN THE MORNING! THIS MUST BE A REWARD FOR MY GOOD ACTION!" Frisk had to let out a silent giggle. He looked so proud; he was probably the only one who would believe them the first time.

* * *

Frisk had only needed five minutes to get everyone into the living room; none of them had complained, not even Undyne who was, fortunately, calmer, and they all were equally intrigued about the situation. Papyrus was almost jumping up and down, and their foster parents were beaming to hear whatever it was Frisk had gathered everyone for - not before giving Undyne a warning about a long talk regarding the usage of spears in the house. Alphys was tapping her claws together, filling the atmosphere with quiet and rhythmic clinks, and Sans, despite at the edge of falling asleep, still listened.

Everyone was in for it. All Frisk had wanted next was for them to believe their story.

They began nicely, telling their loud morning start; Papyrus had grinned proudly at his mention as Toriel sympathetically rolled her crimson eyes, ignoring the killer glare Undyne had set on him. Asgore and Toriel seemed remarkably happy as the human proceeded to explain how they had decided to pay Flowey a little visit, and eyes filled with intrigue as they started to talk about the mysterious object which they then revealed.

In a matter of time, the Nucleus became the center of attention. Undyne had eyed it with awe despite her having seen all sorts of precious crystals back in Waterfall; Toriel and Asgore had commented about how beautiful it was, marvelling at its shape, color and texture; Alphys had inspected it intently, stating that it wasn't a type of stone she had seen before, probably a new, unidentified one; and the skelebros gave it curious glances, Papyrus being the most intrigued of the two.

Everything had been believable thus far; it was when Frisk mentioned Core that their story started going downhill, just as they had predicted.

As they described their colorless self, remarking their broken voice and bottomless eyes, and describing how they had felt, anxious smiles started to slowly shape into frowns, specifically Undyne's and Sans', and others like Alphys and Toriel looked at the human as if they had seen a ghost - not a friendly, shy ghost like Napstablook, but a spirit whose intentions were unknown. Frisk found it difficult to get the right words or phrase their sentences the way they wanted to as they took note of the distrust among them, but they kept going nevertheless, and once they were finished, the disbelieved looks stayed still on the monsters' faces. Obviously, Papyrus was the only one who showed signs of belief, even if he was slightly creeped out by the mention of a gloomy clone of Frisk.

The child sighed. "…you don't believe it, do you?" they finally deadpanned, shoulders slumping in defeat and disappointment - something that triggered an, "Uhh..." from Undyne as she awkwardly glanced down at Alphys, but caused Toriel to stand up from her armchair with a burst of guilt invading her gentle SOUL. She didn't want her child to feel like a liar, even if she herself had trouble believing Core's existence.

"Oh, no, Frisk, there would be no reason for you to lie to us." she told the human sweetly, a furry, snow-white paw caressing their hair. "But... your story was... rather special."

"I think you shouldn't have let them watch five hours of anime," Undyne chuckled, earning a little, nervous smile from Alphys. Toriel only directed her her distinctive angry momma-bear (or goat, rather) glare that silenced the anthropomorphic fish instantly, giving her a slight startle.

"you sure you weren't dreaming, kid?" Sans commented, finally seeming to not mind the fact that he was awake at 7 in the morning and looking more focused into the plight. In all honesty, nobody truly thought Frisk was lying given their absolute trust and friendship towards each other... But, at the same time, nobody knew what to deem their tale as.

"No, it wasn't dream, I-... it's hard to explain, I still don't know what's going on myself either..."

They didn't know what was going on. But they did know how to prove themselves, and their eyes sparkled in realization.

Frisk fixed their sight onto the entrance door. "Follow me," they said suddenly, hurriedly walking towards the entrance and placing an unsure hand on the doorknob as the monsters glanced at each other before joining in - they all looked thoughtful, not knowing what would happen, not knowing why Frisk was so focused on the door. They just played along, seeing how the chances of Frisk lying burned out.

"Core told me that, if I thought of a blank space and opened a door, we'd go somewhere 'safe'."

They hadn't said it like something they were sure of on the slightest, but it was their only chance. If opening the door revealed nothing but their everyday sight, then perhaps the human did dream the encounter. If something, however, did happen... well, they'd have to wait and see.

Frisk took one deep breath, closing their eyes and painting their mind white. They focused on nothing else, just whiteness here, there and everywhere. And feeling their SOUL pulse with anxiety, sending a nervous chill throughout their body, they opened the door.

When they opened their eyes, the plain white space they thought of had gone from their mind to real life.


	3. Confusion Comes in Blue and Orange

The childish hand that opened the door was never enveloped by excitement, or sparkling with high expectations; it was merely curious as it pulled the wooden structure open, inclined more toward the non-expectant side of things without knowing what could possibly be waiting on the other side. Frisk was never one to fully like or believe supernatural stuff, even if the sight of them rejecting certain nerdy lizard's offers to drift off into an anime marathon with her were as rare as heavy rains turning the stifling desert into an ocean.

Then again, those were cartoons, and that was real life.

No, Core's existence hadn't given them a newfound interest on supernatural events; it had very well made it all worse for that matter. Frisk's max was monster magic in terms of phenomena; the mere sight of Flowey's bullets back at the far away beginning of their adventure had already shocked them enough, given the fact that they had always been heavily incredulous about the existence of magic in general before meeting the crazy world that was the Underground. Of course a ghost of themselves would be unfathomable beyond words for the half-believing half-disbelieving kid, then.

They just weren't ready for such affair, much less so if the event chain was shoved into their knowledge so abruptly.

However, all that questioning that unsparingly droned within their troubled mind faded away in an instant, even though the human wasn't precisely thankful about its departure as it had been a much harder to believe fact that pushed it away like a gust of wind would send scattered leaves on a near endless journey through the sky.

As soon as the door revealed the outside, if it could even be called that anymore, a wave of disbelief threatened to attack, and Frisk could have sworn their limbs felt so numb it became hard to stand for a tiny moment.

The flats and trees and bushes and parked cars, even the sky and clouds; all that had once formed their little town had been fully replaced by a pure white void in which not even a sound as small as a fly's minuscule fluttering dared to interrupt the endless cycle of nerve-racking silence. There was _nothing_ that gave proof of life present within. All they saw beyond the door was white there, white here and white everywhere, no other splotch of color present aside from the monsters. The sky, the ground, and all that would be in-between had become whiter than pure snow.

Or straight up disappeared from existence. Either option was equally as valid, and terrifying.

The human's face fell as a silent gasp shaped their face into that of a gaper, their hand rather comically sliding off the doorknob in shock and falling limply to their side as their eyes scanned the nearly blinding color in a fruitless search for even a speck of sand staining the pure coloration. The difference between their baffled expression and someone who had seen a ghost's was microscopic.

In fact, they doubted the sight of an evil spirit floating right across their face would shock them any more than the disappearance of their world would.

"My goodness," Toriel couldn't hold her gasp back as she was met with literally nothing outdoors, hands over her muzzle in disbelief as scarlet eyes slightly contracted and failed to find civilization; Alphys nearly jumped back at the sight that nobody would believe was real had they not been standing right then and there with the perplexed monster family. The thought of everything having been wiped out of existence raced through her mind for a second, and if it weren't for her sight issue, the scientist would have slowly taken her glasses off for a dramatic effect.

Well, not that there was much for her to see, anyways. She'd go with the excuse of not wanting to stand out too much.

Everyone showed astonished expressions as they were met with a dizzying, nearly blinding white taking the place that belonged to the soft colors that the street used to bear back when it existed outside. Papyrus blinked several times, and his head began a frantic search for anything that looked even remotely familiar hidden among the void. Undyne silently mouthed something that could easily be portrayed as a breathless, _'what the hell'_ as Asgore slowly blinked beside her.

After roughly four seconds of gaping that crawled by at a snail's speed, the void stopped being the one sight that shocked them, and their attention regarded something else entirely. Their eyes had only wanted to stare off into the white in a desperate attempt to understand what they had before them and why they had it before them, and it wasn't until they actually tried to search for any signs of life within the empty, monochromatic space that their gaze came across the only thing that was more uncanny, if possible, than the lack of life in general.

Hands innocently behind their back as they stared off into an unknown distance, an eyeless gaze turned to look at the newcomers once the sound of the door opening gave notice of their presence within the pure white mass; the small smile adorning the colorless face seemed relieved once empty eye sockets met many baffled eyes.

"Hello again, Frisk. And company." Core greeted softly, head childishly tilting to the side as they took note of the perplexed monsters who didn't know what to do but stare. Their faces were worthy of winning a horror-comedy award, and the ghostly human had to put inhumane effort into keeping their laughter for themselves.

Had the whole ending-up-in-the-middle-of-nowhere thing been a usual sight for them, Frisk would have smugly turned to look at their family with a cheeky grin as they would rub Core's existence in their faces. So much to prove themselves, but they knew that it wasn't precisely the time to mock the monsters who had thought the child had had too much of a dream for them to handle. Besides, it wasn't like their feeling of being paralyzed by perplexity was helping. Perhaps later, if the suffocating confusion around them ever felt like leaving them enough space to breathe.

Instead, with their mind wondering and pondering riddles that never came close to making sense, the human only lifted their arm in an incomplete wave with half a smile in response to their ghostly welcoming; they were too perplexed to even know what they were doing. Their other self had to titter at the somewhat awkward motion without blaming them for their astonishment as Frisk gingerly stepped forward.

They winced once they did so, not having expected the white mass that pretty much surrounded them to have a solid floor of sorts preventing them from falling into an endless pit. There was nothing below their feet, but at the same time there was something; it gave off an uncomfortable feeling. They made sure that whatever matter was keeping them on their feet wouldn't crumble beneath their fluffy slippers before slowly continuing, looking at the whiteness 'beneath' them intently. It was this close of feeling like floating, and Frisk briefly wondered if their eyes were playing tricks on them before holding the fact that they were actually walking on nothing closer; it wasn't time for complications.

"Careful though. Those who come here for the first time tend to lose their sense of direction."

No wonder – a couple of small steps onward and the void devoured the sense behind the terms left, right, up and down. Frisk no longer knew where they were looking at when they tried to take a short glance around them, and didn't dare to keep walking any further once they were halfway between Core and the door in fear of stumbling or starting to walk at an odd angle, given the warnings that the echoes of an incoming headache were giving them. They decided that it was a better idea to stand still and let Core do the talking and walking; so much white and barely a single reference point, they didn't know which direction they were taking, if any. They could be walking upside-down and wouldn't even notice.

"Wh... where are we...?" Frisk muttered, their eyes aching at the severe lack of color as they attempted to keep their sight focused on their greyscale replica. The same amount of confusion one would carry with themselves when trying to do a math exam with digits and operations unknown to them flowed through the human's words as they spoke, their often childish and vivid voice dwindling into a weak stammer.

Papyrus was meanwhile the first monster to step into the void – or hop, rather –. Undyne came in after him once having made sure that nobody was in danger of falling into a white and endless oblivion, even though each of her steps beamed with uneasiness as she stared into the white space, pupil contracting into a thin slit at the sharp color. Her mouth was half open in shock as she stopped to look around her.

Asgore finally made up his mind and stepped out too, even though he didn't continue as the void's emptiness proved to be too much of a foe for him. The intensity of the color was enough to make anyone lightheaded, and he was one of them.

The other three seemed to prefer staring off into the void instead of joining the craziness. Even still, Toriel's attentive gaze was keenly fixed on the two humans. Through her eyes could be seen a vast mixture of emotions swimming in those scarlet irises, in which intrigue, wariness and almost sadness shone the brightest. She didn't know why, but there was something about Core that made her heart ache.

"This is the Omega Timeline. It's the safe place I spoke of, and where I mostly reside."

Frisk paid no heed to Core's doubt at calling that place home as they attempted to put the information they had just received in order, searching in and out for a meaning that didn't appear to be present within the monochromatic human's words no matter how thorough they could possibly be inspected. It was an honest answer that went straight to the point, yet it sounded like a conundrum that had never been given a proper answer and thus remained a mystery.

The fact that a fearful thought was suddenly pushing the riddle aside was the only thing that stopped Frisk from spacing out trying to solve it. "And… what about our home? The town and everything?"

"Don't worry, your home is fine, and right where it was before you came." Core reassured. Their voice was strangely calm and even soothing despite the slight echo that trailed behind it. "You have travelled here – which means you are no longer in _your_ world."

They blinked. The thought of having just _teleported_ somewhere unknown to mankind struck Frisk like a cannonball, demolishing their viewpoint and faint knowledge on logic. They had never believed that such thing as teleportation was possible – more of a silly thought that could be fun to think of –, and much less teleportation outside of Earth and probably their entire galaxy. And to put the icing on the mixed up cake, with a normal door serving as their… what, time machine? They didn't even know anymore.

The questions grew to be nearly painful as Frisk hurriedly pondered in a desperate attempt to grab hold of an answer to their buzzing doubts. Not a _coherent_ answer, just an answer. Could anybody else get in there, too, by just transforming their mind into a white canvas, or were they just the world's special snowflake? Frisk was lost; the labyrinth that was their situation was too much for them.

At least they knew that they hadn't wiped civilization out, but that was the least of their worries.

"Well, that's one thing, but…" Frisk sighed, mostly in disbelief over the situation. They still had trouble piecing the fact that they were talking to themselves together, and that plus being in a white space to which they had just teleported via a door got them out of the frying pan and into the fire. "I don't know what's going on..."

Asgore finally decided to join the puzzled human as he heedfully eyed the less colorful one, noting the visible distress from a mile away; Toriel, with a cautious gait, followed when she heard her human speak with an afflicted voice.

Papyrus meanwhile adorned the background by flinging his arms around the white space in hopes of stumbling upon an invisible structure – he had gone off with the idea that their town had become invisible, but he was beginning to reconsider it as his attempts turned out to be utterly fruitless. That was the only thing that drove his ornery trainer off her perplexity, focusing on giving him a frown instead.

"It's alright." the monochromatic child softly reassured. Frisk was looking down, clearly overthinking the situation they had fallen into. "Settle in, relax. I understand your confusion; this is not easy to comprehend. We are not in such a hurry anymore, so take your time."

Asgore shifted slightly as his pondering human looked up at him for guidance; they were nervous and at a loss of words, even with Toriel's reassuring paw resting on their shoulder and sending off soothing vibes through them. "So... you are this... 'Core' human Frisk told us about, yes?"

Frisk respected their foster father for staying so calm despite all he had to take in so suddenly. He was a serene and gentle king that always preferred to take things easy as to keep everyone composed – he wasn't prepared to be introduced to a ghostly human he hadn't quite believed existed until meeting eye to eye – or, eye to eye socket –, much less appear in a white oblivion, and all so abruptly.

Neither him, nor Toriel.

They were confused, and that was a fact; but both knew not to let it show under _any_ circumstances. All it took was just one respectable figure that was looked upon let the fear of the unknown take over to start a panic attack.

It was a fiery chain, and they knew the chaos it could unleash by experience. First it would be Asgore to not know what to do, then Undyne would react violently, then Alphys would lose her frail nerves, then Papyrus would freak out, and so on. Funnily enough, that had been first caused because of a spider in the house. Heavens know what would happen if either of the two boss monsters lost their composure over a _whole new world_.

Toriel was fully unwilling to let everyone lose their nerves, and the king wouldn't be the one to allow such mayhem to break loose. Again.

The greyscale human nodded at his inquiry, and the furry white face became adorned by a warm, reassuring smile. It was the comforting type of smile that Asgore and Toriel always performed so well – speaking of; the motherly goat was also smiling, even though there was something on her mellow expression that felt pained.

That mixed feeling was there again, stronger with Core in front of her. The fact that they looked like a hopeless reflection of Frisk wrenched her heart with the might of a titan; the greyscale coloration and empty eyes screamed gloom.

"Well, it is nice to meet you." Asgore said softly. "I must say you are quite the interesting human."

"It is indeed," Toriel agreed, trying to put her disheartening thoughts aside before adding a gentle, "It is rather strange to be talking to another Frisk, yet intriguing. Now, I would begin our introductions, but Frisk has told us that you may know who we are?"

The human had only guessed that when they had explained their double's existence, but it wasn't a farfetched guess. Core knew their name, after all, and the excuse of them being their other self wouldn't count as they knew Flowey's too. Really, the mere fact that they were _another_ Frisk screamed that they shared the same knowledge on things. Not only that, but they had mentioned 'their friends' back there, so it was clear that the monochromatic human knew what was going on.

As to how much, exactly, Frisk didn't know, but Core probably knew enough.

It was helpful, yet unsettling. There it was, a doppelganger of every monster's favorite human that apparently knew all of their friends and had a seemingly vast knowledge on things never before seen by human or monster eyes. It wouldn't be strange to not believe it – it would be strange to not find it absolutely unnerving, despite their calm, mature and reassuring demeanor.

"I do indeed. As to why, it will all be explained shortly." Core took their sight off the much taller monsters to glance at their other self. "After all, I do owe you several answers, don't I?"

Frisk couldn't help but feel just the slightest bit of excitement almost sparkle through their eyes as they gave a single nod with a smile pulling at their lips. The army of questions was really driving them mad, and they could still feel it adding more and more inquiries to the skyscraper-high pile. Explanations were welcome and appreciated, even though the human had a feeling that they would struggle to understand it all.

They were talking to their reflection on a colorless mirror whilst inside a void, for everything's sake! Of course they would struggle to pull that slippery explanation close enough to inspect it for as long as they needed to. Years, probably, but they would swallow that little detail and pay more attention to the incoming answers than the nerdiest of humans would.

"We'll need some time, though, won't we?" Frisk sniggered, their previous confusion dissipating as their eyes briefly flickered over to the muddled monsters behind them; Asgore looked over his shoulder as he took the hint, and really, he couldn't help but show a small smile. Unforgettable family moments were still unforgettable family moments, no matter if they were lived in the Underground, on the surface, or in an empty space that was probably outside of the entirety of the known universe.

Sans and Alphys had finally stepped into the void too, the latter nearly having lost her footing given the fact that her perplexity over the senseless situation that surrounded her made her stubby legs feel numb, and the superlative whiteness poked her sensitive eyes unsparingly. Papyrus was leaning all of his ideas about the void – literally being screamed rather than told, fact that allowed them to hear something along the lines of a challenge set up by their neighbors – over Undyne, who had previously stabbed a spear into the 'floor' to make sure it was indeed solid before the C word held her attention span away from her plan.

Alphys had gaped at it and Sans contemplated it with dull hints of interest. The tip of the spear had actually gotten embedded into whatever the heck that floor was made out of, and it looked like a headless spear floating in the middle of a white abyss; it was almost some sort of visual trick.

Looking at the scene, Core couldn't help but chuckle. "May be the case."

They sighed silently. _'Some time'_ was nowhere close to the time they would actually need to explain the situation, let alone wait for the monsters to actually comprehend it. Core was not going to be the one placing blames on each monster that repeated a question as they would fail to grip the answer, but it felt weird to have so much to explain. They had always only needed to explain the Omega to those that came in, and that was about it; but of course, people of the Multiverse had a better idea of what was happening around them, so in-depth lessons had never been necessary.

Sometimes, it was a shame that the Alpha Timeline couldn't be introduced to the Multiverse without a life or death reason.

 _"oh my gosh!"_

It was almost funny how everyone stopped what they were doing, be it talking or gaping, to crane their heads toward the new sound as a voice they had never heard before broke through the overall silence that had thus far only been pierced by certain tall skeleton.

The perpetrator was a cheerful and slightly bombastic voice, somewhat youthful and eerily reminiscent to that of Papyrus' in terms of tone, but not quite as high pitched; somewhere in-between, and softer.

Core seemed both upset and annoyed by its sudden presence, though their emotion balance was more inclined toward the latter as their head followed something behind the two monsters and human. The three turned around to mimic their movement, and were met with the only other thing that could actually make them believe they were going crazy.

Another Sans, somehow bluer, was running straight toward the bunch, and Frisk was sure his eyes were shaped like... stars?

He stopped abruptly seconds before colliding against Alphys into what would have been a bear hug capable of breaking someone in two, given his obvious joy, and the scientist took a couple of tiny steps back with a baffled whimper caught on her throat when she saw the starry, heavily smiling face almost inches from her pointy snout. It was an apparently harmless and plump-looking skeleton that ran over to her encounter, but her eyes saw a blue train out of control about to crash into her.

First a ghostly Frisk, then a more cheerful Sans? _What was going on?_

"hi alphys! oh, i'm so glad to see you, i thought you were… _gone_! and- and did your eye just heal? that's awesome!" He looked like he was bouncing on a trampoline and his star-shaped eyes were reminiscent of an out of control metronome as he spoke, frantically glancing left to right as he scanned the new presence within the Omega – only thanks to that, his attention seemed to have caught hold of Undyne as he looked happily at her.

He waved his gloved arm high in the air. "oh, oh, nice to see you too, dr. undyne!"

Said fish monster didn't know what was more worthy of her freak-out: the fact that Sans was as cheerful as his brother, or the fact that she had been called 'doctor'; her expression was thoughtful and aimless as she kept repeating the word inside her mind in case she had missed something important regarding her title.

Alphys' confusion wasn't all that far from hers. She didn't know what to do with all the sheer amount of happiness given to her existence, and it put her mind to work into making an answer. She had never had a ruined eye…?

Sans' euphoric clone glanced over at Asgore and Toriel, looking at the edge of screaming his joy out. "hello there, your majesty!"

It struck Toriel that he had been looking at _her_ when speaking of such title.

"Thanks for listening to me when I told you to wait," Frisk turned their sight away from the punny skeleton's replica at Core's sarcastic and somewhat vexed comment, and did a double take as they caught a glimpse of something orange and tall standing next to the monochromatic child.

An O defined the shape of their mouth as the human gaped at the other Papyrus, who shrugged Core's comment off as he calmly said, "DIDN'T TELL US 'TILL WHEN, SO." with a voice that was nowhere near as loud and booming as the skeleton they all knew's was. Toriel seemed more distraught by the fact that a lit cigarette was clenched between his teeth than by the fact that his existence was a thing. Others' health held more importance to her than their completely incorrect existence.

Did skeletons have lungs?

If a pile of confusion hadn't landed on top of them, Frisk would have laughed at the way Asgore exchanged glances between the careless copy of Papyrus and the joyful Sans trotting all around the baffled family, but said pile was keeping their mouth wordless and they found themselves doing the same thing before they even realized. The situation deserved every bit of their bewilderment, after all, and the amount of ideas they were getting was heavy enough to pull them down.

"Um… Greetings, I suppose?" Toriel couldn't help but frown, still with a smile as to not appear rude, as she looked at the Papyrus clad in orange. It easily became an overly odd sight to see 'him' so carefree; smoking, dressed without standing out in a crowd, and with such a happy-go-lucky personality from the little she had seen thus far. Same case applied to the ecstatic Sans the other Papyrus seemed so focused on. It was just unnatural of him to even raise his voice, but now his childish replica was doing everything he would never do.

It was like the world had turned upside down, and Toriel felt like she was missing something obvious about the two.

"SUP." the skeleton replied casually with a single, friendly waggle of his eyebrows, their Papyrus' characteristic wide grin shaped on his face as he spoke. His seemed even wider, but in more of a chill manner as opposed to the typical proud and confident one. His overall demeanor reminded her of Sans, and that feeling of the obvious buzzed louder. Frisk was at the edge of grabbing hold of it, too, but their mind was too scrambled to think about it properly.

The other Sans seemed to have stopped marveling over Alphys, Undyne, and the boss monsters nearby as he walked past a seemingly addled Sans, and all the joy that exploded after each of his steps suddenly came to a halt as the two stared at each other under Papyrus' pensive glance for a few seconds. It was the plump skeleton who broke the silence, even though his voice had noticeably dwindled and sounded like a whisper in comparison to the utter glee he had been screaming just seconds ago.

"oh, uh..." The more childish replica of Sans seemed rather confused as he glanced behind him to make eye contact with Alphys and Undyne, a contemplative finger taping his rounded chin as he then looked over at Frisk and the others. Something appeared to have clicked on his mind as he looked back at the two skeletons, losing his cheerful smile, and with a blink the stars that defined the shape of his eyes morphed into two blue circles.

"wait... you're not from my universe, are you?"

The word 'universe' reverberated around Sans' skull, and Papyrus felt like he had been introduced to a puzzle more complicated than Hotland's and his own together. The sky-blue skeleton sounded disappointed, but Sans just blinked the confusion away and replied with a frowning, "no...?"

"aw…" His replica's shoulders slumped slightly. "i'm sorry, for a second i thought you all came back…"

Before either of the two other skeletons could utter a word, he briefly shook his head all of a sudden. He had gone from looking like the saddest skeleton in the world to one who had left the most important thing ever behind and just remembered it.

"oh! that means we haven't met yet!" he exclaimed with newfound euphoria as gloved knuckles were proudly placed on each side of his waist. His eyes were no longer stars, but they sure did twinkle like so, and Sans felt like he was staring at his polar opposite. Or, the vision of him having had too much sugar had come to life. "i am the magnificent sans, pleased to meet new friends! even though people call me blueberry here so we don't get mixed up. mweh heh heh!"

Sans had to give his brother a sideways glance instead of questioning literally every word his joyful doppelganger had said; he, with the most appropriate of nicknames, acted just like Papyrus, with a slight childish speck to the mix.

He found it adorable for some reason.

"WOWIE! SO FRISK HAS A VERY GREY CLONE, AND SANS HAS A NON-LAZY ONE!" Papyrus stepped forward, almost literally pushing all the things that didn't make sense aside as he crouched in front of Blueberry with that overly friendly sparkle illuminating his black eyes. A new friend, especially one so interesting, was most definitely more important than senseless words. It was nice to see his brother that wasn't his brother so ready to take on the world.

"I AM THE GREAT PAPYRUS! AND I. . . ADMIRE YOUR CLOTHING CHOICES!" He beamed at Blueberry's all-too blue outfit, and the gleeful skeleton took a brief look at himself before meeting cheerful eyes with his own, once again starry at the compliment.

"thanks! i really like yours too, it makes you look like a superhero!"

"BUT OF COURSE! SOMEONE AS GREAT AS ME MUST LOOK LIKE ONE, FOR I WILL SOME DAY BE CONSIDERED A HERO! NYEH HEH HEH HEH!"

And as the two gladly rambled on and on about their battle bodies and greatness, Core, Frisk and the three other monsters joined the quandary; the more colorful human sported a crooked smile on their face as they took note of the wide-eyed scientist and warrior, who stared at the beaming skeletons without clue of what was going on. Alphys was pretty much questioning life at that point, and Undyne feared she had forgotten how to breathe.

Sans blinked at the other Papyrus before glancing back at the two monsters who had become best friends in matter of seconds, and with good reason. "so, are these two supposed to be me and paps with exchanged personalities or something?" It only took him a moment to realize the obvious, even though he had trouble believing it in the first place.

"That's just what I was thinking," Frisk commented in realization, and Toriel blinked as she finally understood the subject she had been pondering on – she mentally called herself a dork for not realizing sooner. It was more than obvious that those two were their opposites in flesh and blood.

...sort of.

"They are, even if it's rather difficult to understand." Core proved their suspicions true, and sighed. "You were not supposed to be introduced to the alternate universes so early." Core's voice gained a small growl as they looked at the other Papyrus with annoyed eye sockets, but he wasn't affected by that.

"YOU KNOW HOW HE GETS WHEN NEW PEOPLE COME IN HERE." The cigarette was taken between two bony phalanges as the easygoing skeleton sighed, a small puff of smoke coming from the brief exhale. "YOU SHOULD'VE TOLD HIM. IT'S SORTA EASY TO MISTAKE THESE GUYS FOR OURS, ESPECIALLY AT FIRST SIGHT."

Core looked down with a pained smile, and Toriel had a strong feeling of wanting to ask any trouble ahead – such was her motherly instinct –, but she believed the subject was more personal than anything, and she was still puzzled about what was happening in general. Later would be a better time for questions.

There was definitely something wrong, though.

"huh. that explains a few things." Sans commented. His brother and his not-brother were both laughing proudly, and it was difficult to tell which laughter belonged to whom in the intertwined _nyehs_ and _mwehs_. Both had adopted the same posture – it was as if they were looking in a brotherly mirror, and the blank space helped at giving off that illusion.

Sans had given his own impression of Papyrus for the sake of pissing him off before, but he'd never thought he would see the real deal. Blueberry was definitely better at impersonating his brother than he was. Or _being_ his brother, rather.

"H-hold on..." Alphys finally spoke, pushing her droning doubts aside as a certain word she had only heard in fiction caught her attention. "Did you say... a-alternate universes?"

"Yes. Alterations of your world, such as the one these two come from." Blueberry looked at them on cue as Alphys mulled over the answer she had been given; despite his previous disappointment due to reasons unknown, he looked as happy as one could possibly be and more. "Even though they are Sans and Papyrus too," the monochromatic child continued. "we have nicknames that they agree with, so that the many different monsters alike that come here don't get mixed up with each other."

"Wait... there's even _more_ of them?" Frisk chimed in, unable to keep their surprise for themselves.

"Nearly infinite universes, actually. All of you has many, many alter-egos."

Core's answer left them gaping; as if suddenly meeting their gloomy double wasn't enough... Alphys kept her eyes locked onto them as a storm of thoughts momentarily paralyzed her before panning her sight to each swapped skeleton; Undyne's fins dropped in disbelief.

"These are Carrot," A colorless palm extended toward said skeleton next to her. "and that over there is Blueberry." The monster clad in blue smiled proudly at his mention. Undyne couldn't help a brief snigger escaping as she tried not to burst out laughing at the aliases, and Sans feared she would start calling him Blueberry from then on. Carrot wouldn't work with their Papyrus, lucky guy, but the short skeleton was almost always seen with blue – in other words, he was a walking, bony dartboard.

Oh boy. He would so paint his sweater another color if Undyne – heck, or even Toriel – decided to start giving him that name just for the sake of pissing him off.

"They are from the alternate universe we refer to as Underswap."

"REFERRED." Carrot corrected them in a whisper, the cigarette back on his jaw as a tired hand went back to his pocket; the greyscale human seemed upset at the correction, but they were anything but showing more hidden sadness than the swapped Papyrus' words sported.

"And... what exactly are these 'alternate universes'?" the king inquired. Nobody had seen him so curious and intrigued since the memorable day Alphys introduced him to anime. It almost felt like yesterday when Frisk's family began to bond down there... good times. "I don't quite understand the meaning of 'alterations of our world'."

Core nodded in understanding of it being a complicated matter as Blueberry bounded over to his brother, sensing a story from miles away. "For you, it may be difficult to comprehend." They shifted slightly as they began their explanation; the skeleton clad in blue looked at them intently, despite having heard the tale many times before. It was never enough for him.

"See, you actually live in a complex and fragile... entwine of worlds, per say, that we call the Multiverse as a whole. It houses your timeline, referred to as the Alpha Timeline, and this at the same time houses the alternate universes, which 'branch' from it. They are called AUs for short."

There was nothing more to it – that was _the_ explanation that solved the question of what the Multiverse was, yet the sea of thoughts that formed the monsters' minds had become an unstable ocean; waves of confusion and whirlpools of riddles destroyed all calmness among it. Alphys was no longer the only one profusely questioning life, and more than one monster (and a human) had forgotten how to breathe.

"Oh... That is... a lot to take on." Toriel sighed, her voice nearly drowned out by astonishment. Most monsters, herself included, wanted so badly to say that such thing couldn't possibly happen, yet they had three clear examples painted in gray, blue and orange right there. And still, their presence felt so eerie and wrong.

"Alright, let me get one thing straight." Undyne suddenly said. "In the place where these guys come from, _all_ of us are swapped?" The tone of her voice was a fiery questioning one. Her eyes pierced daggers into Core in search for straight answers.

"Yes."

A pause. "...so _I_ would be the nerd? And Alphys the totally awesome warrior?" Her voice increased in terms of euphoria as she spoke, a fanged smile adorning her wide grin, but she still sounded at the edge of roaring in anger.

"Yes."

She paused again, and Core feared she was going to burst in a cyan explosion of angered spears at the fact that another version of herself was a dork as opposed to a fierce warrior from whom the strongest of humans ran away from. She didn't take that kind of stuff all that well; bless the poor soul that dared to call her a nerd in her face.

"That's... freaking AWESOME! Oooh, I need to meet those guys!"

Unexpected.

Through her sudden joy over something as interesting as an alternate reality was, despite the lack of sense and logic and everything within that subject, she hadn't caught Carrot growing uncomfortable and Blueberry's smile slowly and only slightly vanishing. She only gave them her attention when Core tugged at it.

"Undyne, please... that's a very touchy subject now."

She stopped awing in her mind when she finally saw the upset glances of the swapped skeletons, and her toothy smile dropped. It wasn't on her agenda to make the innocent feel bad, though she didn't know what could possibly be so touchy about wanting to meet her nerdy self.

"it's okay, core, she didn't know." Blueberry said calmly, but it was obvious that the mellow voice he spoke with was acting as a shield that hid a teary and deeply dishearted tone.

"Know what?" the confused fish monster asked, her voice losing its livid spark.

"...long story." Core deadpanned; the sideways glance Carrot was giving them seemed to have stopped their answer. "We will tell you later on."

* * *

 **A/N**

 **Didn't want to end the chapter here, at first, but it was necessary because there is a cliffhanger on the next chapter and it would be too short if I stopped this any further. And this is kind of a mild-cliffhanger too. Yes, I am that cruel ^^**

 **...I'm so bad at portraying confusion dammit.**

 **Also, yes, this follows an 'alternate end' of mine to the AskError comic that will be explained later on, in case you were wondering.**

 **In reply to Idk lol: no, Gaster is not the antagonist and I don't think he's even going to appear in the story at all. Our antagonists are Error and Nightmare. Fresh is a veeery secondary (and accidental) antagonist too.**


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